export default function (self) {
  "use strict";

  self.test_blob = (fn, expectations) => {
    var expected = expectations.expected,
      type = expectations.type,
      desc = expectations.desc;

    promise_test(async (t) => {
      var blob = fn();
      assert_true(blob instanceof Blob);
      assert_false(blob instanceof File);
      assert_equals(blob.type, type);
      assert_equals(blob.size, expected.length);

      const text = await blob.text();
      assert_equals(text, expected);
    }, desc);
  };

  self.test_blob_binary = (fn, expectations) => {
    var expected = expectations.expected,
      type = expectations.type,
      desc = expectations.desc;

    promise_test(async (t) => {
      var blob = fn();
      assert_true(blob instanceof Blob);
      assert_false(blob instanceof File);
      assert_equals(blob.type, type);
      assert_equals(blob.size, expected.length);

      const ab = await blob.arrayBuffer();
      assert_true(ab instanceof ArrayBuffer, "Result should be an ArrayBuffer");
      assert_array_equals(new Uint8Array(ab), expected);
    }, desc);
  };

  // Assert that two TypedArray objects have the same byte values
  self.assert_equals_typed_array = (array1, array2) => {
    const [view1, view2] = [array1, array2].map((array) => {
      self.assert_true(
        array.buffer instanceof ArrayBuffer,
        "Expect input ArrayBuffers to contain field `buffer`"
      );
      return new DataView(array.buffer, array.byteOffset, array.byteLength);
    });

    self.assert_equals(
      view1.byteLength,
      view2.byteLength,
      "Expect both arrays to be of the same byte length"
    );

    const byteLength = view1.byteLength;

    for (let i = 0; i < byteLength; ++i) {
      self.assert_equals(
        view1.getUint8(i),
        view2.getUint8(i),
        `Expect byte at buffer position ${i} to be equal`
      );
    }
  };
}
